Plasma displays operate by selectively exciting an array of glow discharges in a confined rarified noble gas. Full color displays are made by generating a glow discharge in a mixture of gases, such as He-Xe or Ne-Xe gas mixture which generates ultra violet light. The ultra violet light excites phosphors to produce light of the desired color. Such displays have been described in an article by A. Sobel entitled "Plasma Displays" in IEEE TRANSACTIONS ON PLASMA SCIENCE, vol., 19, no. 6, Dec. 8, 1991, pgs. 1032-1047 and in an article by P. S. Friedman, entitled "Are Plasma Display Panels a Low-Cost Technology?", in INFORMATION DISPLAY, October 1995, pgs. 22-28.
As shown in FIG. 1, a typical plasma display panel 10 comprises a rear glass substrate 12 having a plurality of substantially parallel, spaced first electrodes 14 on a surface thereof. A thin layer 15 of a dielectric material, such as a glass, covers the electrodes 14. Barrier layers 16 are on the surface of the glass substrate 12 between the first electrodes 14. The barrier layers 16 project from the surface of the substrate 12 a distance greater than the thickness of the first electrodes 14. Red, green and blue (R-G-B) phosphor layers 18, 20 and 22 respectively overlie alternating first electrodes 14 in the spaces between the barriers 16. A front transparent glass substrate 24 overlies the rear glass substrate 12 and rests on the barrier layers 16 so as to be spaced from the rear glass substrate 12 by the barrier layers 16.
An array of substantially parallel, spaced second electrodes 26 are on the inner surface of the front substrate 24 and extend substantially orthogonal to the first electrodes 14. A layer 28 of a dielectric material, typically glasses, covers the second electrodes 26. A layer 29 of MgO covers the dielectric layer 28. Voltages applied to the electrodes in the proper manner excite, maintain and extinguish a plasma in the gas within the region formed by the barriers at the desired times. Addressing of individual pixels is done using external circuitry at the periphery of the panel. Barrier structures ar typically used to confine the discharge to the pixel addressed, eliminating both electrical and optical cross talk between adjacent pixel elements.
In an AC plasma display, the columns of pixels are separated by the barriers, and the first electrodes are arranged beneath the gaps between the barriers. In a DC plasma display, the barrier structures are typically crossed, providing a box-like structure at each pixel element. In the current state of the art, the barriers are formed by multiple, high-precision silk screening steps which cumulatively provide barriers of the desired height and aspect ratio. The height to width aspect ratio for the barriers is determined by the reproducibility of the screening steps and is typically limited to a value of two or three, thereby limiting the obtainable pixel density. It would be desirable to have an alternative means for forming the barrier structures that involve fewer processing steps and provide higher aspect ratios.